﻿using Microsoft.Xaml.Behaviors;
using System;
using System.Windows;
/*
 * 源码已托管：https://gitee.com/dlgcy/WPFTemplateLib
 */
namespace Solatys.Helpers
{
    /// <summary>
    /// 在行为中使用的 路由事件触发器（支持附加事件）
    /// 调整自：https://sergecalderara.wordpress.com/2012/08/23/how-to-attached-an-mvvm-eventtocommand-to-an-attached-event/
    /// </summary>
    /// <example>
    /// <code>
    /// &lt;b:Interaction.Triggers&gt;
    ///     &lt;helpers:RoutedEventTrigger RoutedEvent="local:YourAttachedEventHelper.YourAttachedEvent"&gt;
    ///         &lt;b:InvokeCommandAction Command="{Binding YourCmd}" EventArgsParameterPath="OriginalSource"/&gt;
    ///     &lt;/helpers:RoutedEventTrigger&gt;
    /// &lt;/b:Interaction.Triggers&gt;
    /// </code>
    /// </example>
    public class RoutedEventTrigger : EventTriggerBase<DependencyObject>
    {
        /// <summary>
        /// 路由事件/附加事件
        /// </summary>
        public RoutedEvent RoutedEvent { get; set; }

        protected override void OnAttached()
        {
            FrameworkElement associatedElement = AssociatedObject as FrameworkElement; 
            
            if (AssociatedObject is Behavior behavior)
            {
                associatedElement = ((IAttachedObject)behavior).AssociatedObject as FrameworkElement;
            }

            if (associatedElement == null)
            {
                throw new ArgumentException("Routed Event trigger can only be associated to framework elements");
            }

            if (RoutedEvent != null)
            {
                associatedElement.AddHandler(RoutedEvent, new RoutedEventHandler(OnRoutedEvent));
            }
        }

        void OnRoutedEvent(object sender, RoutedEventArgs args)
        {
            base.OnEvent(args);
        }

        protected override string GetEventName()
        {
            return RoutedEvent.Name;
        }
    }
}
